MADISON, Wis. -- There is a growing concern on the Illinois-Wisconsin border over the emerald ash borer.

The tiny insect called has been found 40 miles away from Rock County, near Dekalb, Ill.

If just one ash tree is found to have ash borers, all the other ash trees within a half-mile radius must come down as well, WISC-TV reported.

The University of Wisconsin Extension Service held an information seminar on the emerald ash borer Wednesday night.